How To Synchronize Near Realtime Reads From A Sql Server Table
Sep 12, 2011
We have a reporting app thats needs to update it's charts as the data gets written to it's corresponding table. (the report is based off just one table). Currently we just keep the last read sessionid + rowid (unique combo) in memory and a polling timer just does a select where rowid > what we have in memory (to get the latest rows added). Timer runs every second or so and the fast sql reader does it's job well. So far so good. However I feel this is not optimal because sometimes there are pauses in the data writes due to the process by design. (user clicking the pause button on the system that writes data). Meanwhile our timer keeps hitting the db and does not get any new rows. No errors or anything. How is this situation normally handled. The app that writes the data is separate from the reporting app. The 2 apps run on different machines. Bottomline : How to get data into a c# app as and when it is written into a sql server table without polling unnecessarily.
I have a simple Windows Service that reads from an Excel spreadsheet and imports the records into a SQL Server 2000 database table. Before it loads it checks if the file has been successfully imported before (using filename) and whether any of the records in the file have been imported before (using primary key). If these checks are ok I load the records into a datatable and then update the datatable to the database.
However, I need to do this in a transaction as I want to ignore the whole file if there is an error. The file goes to a discarded folder and the user gets an email with why the import failed. (This is likely to be because the store the record is for is not yet added to the database and the referential intergrity of the db fails). If there is no transaction the records before the failure record are imported. When the file is imported again (the store has been added to store table) the file is then rejected because duplicate records are already in the db.
I have a small application in ms access for student information. which is on my sever.now I have same application in .net and sql server which is online in my website, while access application is on my pc...Now I want that, If i make changes in my access application, the data must be copied to my online application automatically,Same thing i want vice versa,means if i make changes in my online application, the data must be copied to my desktop database.
I am writing a windows service that will read records from one table and write them to another table. Problem is when i declare cmd = New SqlCommand(l_sSQL) the code stop executing but the service will still be running. I can insert into the other table using the service but i cant read from the other table.
Code Sample:
Private Sub dbcon() Dim con As New SqlConnection Dim cmd As New SqlCommand Dim adapter As New SqlDataAdapter
I want to develop a small application that reads in scanned barcodes into a database table - Would a vb.net form based application that connects to the database be best approach? What I'm think is each time the user scans in the barcode - a message appears on the form saying the barcode that has been scanned.
1.Would I need to program anything within the program to check whether the barcode scanner is connected (or is this not necessary since it works like a keyboard device?)
2. How could I automate the scanning in without requiring any user intervention like a button which saves it to the database - so basically as soon as a barcode is scanned in - it is saved to the database and the next barcode can be scanned in etc.
im makign a game that reads text files off of an ftp server. everything is working great. except for the fact that i cant read more then the first line of the players text file. how would i use substring to, for example, look for 'inventory' and get all the info under 'inventory' and above the next title?
I have a hardware which sends out packets containing 17 bytes to the comport in bursts of 3. the little test VB that I have written receives and displays the bytes in a line of 17 bytes long and works fine until it gets to around 170th packet, then it starts to mix up (looks like shifting the data left) the bytes shift mostly by one digit sometimes by two. then it will continue to give almost a packet correct and a packet shifted for about 50 packets. Then it will correct itself for a long while, but then the speed at which it receives drops. All the packets are sent 3 times, and before things go wrong (within the first 170 packets) the packet counter shows that it receives 3 packet each time but after the problem it goes to 2 packet per burst and then to one.
If i close my VB monitoring program say at packet 165 and immediately open it again, it wont go wrong for another 170 packets, this points the finger at VB. I have check my hardware, there is no problem with that.The program reads port - waits for 17 bytes - once 17 has been received it will go and buffer the packet in an array. In fact they are 2 arrays but printing fro either results in the same problem.I have tried whatever i could think of but to no avail, i am wondering if some kind of house keeping needs to be done to clear something... I am sorry the program is a bit messy but I have been making many changes to find out what the problem is - my code below:[code]
I have a VB.Net project that creates a new Webbrowser instance which then navigates to a page in order to read the HTML into a variable ( then modify this before displaying in a visable webbrowser).The issue i have is that the webbrowser navigate just reads the page from the cache and does not read it from the server.
I am working on a windows application project on NIST time synchronization, but can't get a proper solution for it. If anyone can send me the code to synchronize time from the global time server in VB.net or C # code
I have a query that I have to run that requires me to get rows from a table based on the value of a field in another table (which I have gotten earlier). I currently have it done like this (simplified).
I am working with a Vb.net 2005 application. On the application I have a Create table button which when clicked creates a table in Sql server with the code shown below;
Code: Private Sub BtnCrtTable_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCrtTable.Click
[Code]...
This is really a pre-defined table and the data is already specified to be inserted to the table. However, my primarily task is to read a flat file which has the data and consider the first line as the column to be column names.
Therefore, initially I created an open dialogue to browse for the text file and store the path such as E:Datafile est.txt, in a TextBox1 visible at run time. Now the task is to change the above "create table" to read the txt file (column names are on the first line) and then create the table in the database.
i two tables named tblaccess(nID,nRoleID,nModuleID,cAccess) andtblmodule(nModuleID,cModuleName) and i have a datagrid which is bounded to tblaccess. the problem is, I want to display cModuleName from tblmodule instead of nModuleID. please tell me how.
synchronizing a combobox with a textfield. I have a form with a textfield and a combobox. The combobox is populated with the department name from the database when the form loads. I would like the textbox to display the corresponding department number when the user selects a department name from the combobox. I have tried using the SelectedIndexChanged event of the combobox but I can't seem to code it to work. This is the code I'm trying to use but it is displaying "DEPARTMENT" in the textbox. Department Code is the primary key of the table.
strSQL = "SELECT * FROM DEPARTMENT" Dim da = New OracleDataAdapter(strSQL, cn) da.Fill(dSet, "DEPARTMENT" )
I'm trying to get my application to restore the default values of my application settings but every time I click the Synchronize button it says: No user.config files were found in any of the following locations. I have never before tried to synchronize this application and am working with Visual Studio 2010. [URL].
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged If ListBox1.Text = "kg" And ListBox2.Text = "lbs" Then
I have my client app installed in many computers, each computer is connected via LAN. Each Client app uses its own SQL database. I need to synchronize the databases in each computer so that every client app has the same data. How can I achieve this using VB.net (VS 2010 , Winforms)
I have two datagridview with same columns. When user resize the column of one of the datagridview during run time, then another datagridview column will synchronize to resize as well..
With my program I wanted to change the fixed connection string to a User entered one. So in the application settings I added DBConnectionString as a user define String. If the string if empty, it shows the window where one can add the server, database and user name / password. If you press the OK button, it saves the settings:
Private Sub LDBOKBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LDBOKBtn.Click ' ----- Server name is required. If (Trim(LDBServer.Text) = "") Then MsgBox("The Server or Host name is required.", _
[code]....
The problem is that when you press the same button to show the System Settings again, the ConnectionString is empty again. So nothing was saved.
I have written a stupid backup utility that copies new or modified files. That's fantastic until I come across files that are 11 GB in size that have been modified. I have a feeling I can compare the file to be backed up and the file that will be over-written (old version of file) and "synchronize" the file instead of copying the entire 11 GB.
How can i synchronize dragged controls (in my application), so they maintain their relative position to each other? is there some API function or .net method that can do this?
I am having a remote server it has INVENTORY DATABSE , and also iam having same databse in my local system. I want to populate by local database table with my Remote database table through Vb.net code by click a button. How to do this .
I use a dbDataAdapter to populate a DataTable from an unlinked oracle database.I have a dbDataAdapter that I want to insert rows into an SQL Server table using SQLCommandBuilder.I have been trying all day to update the DataTable that references the SQL Server table with the data from the Oracle DataTable so that I can insert the rows.
i wanted to make a pinging program that could send pings to websites, i have all the code written, i just cant get it to display what is going into the cmd in a text box.... The reason i am having trouble with this is because the code says " output = (process.StandardOutput.ReadToEnd)" it will only display it in the text box AFTER the code has finished....
I am writing an application in VB .NET which calls external executables (written in C++)and passes them some command line arguments. What I need to do is read back their stdout outputs inealtime , i.e. as they run.I am currently using the ProcessStartInfo class and setting the RedirectStandardOutput property to true and reading it back in from a StreamReader. However, I cannot read this back in realtime. Once the process finishes, the StreamReader will allow me to
I'm currently working with a project where I need to transfer the internal audio (sound from the computer) to another computer and play it back there.
I thought of transferring the audio with a TCP server-client connection since I already have the knowledge of how to do that.
My problem now is that I don't know how I would capture the internal audio and how to be able to play it back as a stream on the target computer. I have searched a bit and many people recommend using MCI but I'm not sure if this will work on an "almost realtime audio stream" connection.
So my question is: What is the best way to grab the audio from the computer and then play back the data on another computer (as a stream)? I want to do it in realtime and not "recording" the sound and then send it to the target computer.
i am trying to make a simple scripter. my scripter has a Run button to run the written scripts in a RichTextBox.But in new version of my program i want to make a RealTime run scripter, So don't need to a run button and scripts should process when user type in richtexbox. a way that i had used in my program is this :
On Error Resume Next FileOpen(1, "c:windowsmagico(test).txt", OpenMode.Output) PrintLine(1, frmMain.page_script.txtScript.Text)
I have hit a brick wall with my latest project.In essence the entire tab control is created on the fly, i have successfully added any number of tabs with the tabpage title being filled correctly. my problem however is when i add the content itself to the correct page, i have no item displayed on any tabs and however i can retrieve the contents and change them with code.
My code takes a pricelist xml file from my works website and my code is supposed to allow this content to be edited and returned to the server with adjusted prices to reflect updates in our costing. All the code works except the part to display the data, and consequently the code to use this data to update the array used for the xml while the program is running is not written.
I have a class that contains a List(of T) used in a multithreaded application. I have three methods Get, Add and Remove where these access and modify the List(of T). I was using SyncLock to lock m_List any time I queried it for the desired object as well as when I added or removed objects. However I'm curious as to if there is a performance gain by simply locking m_List when I add an object or remove an object as opposed to when I'm searching for a desired object?
